1. Field of the Invention
This invention relates to a tool for removal of a chisel from a chisel holder, having an actuating member, which has a push-off section, wherein the actuating member can be displaced along a displacement direction.
2. Discussion of Related Art
A tool is known from PCT Reference WO 97/23710 wherein a pin-shaped push-off section is connected to a handle by a hinged connector. The tool is employed for the removal of a chisel inserted into a receiving bore of a chisel holder. The receiving bore is embodied as a through-bore, so that a chisel shank of the inserted chisel is accessible from the rear. A security element is drawn up on the end of the chisel shank, which is held in a groove of the receiving bore and thus maintains the chisel in the chisel holder. If the chisel is to be replaced, for example after reaching a wear limit, the push-off section is pushed through the rear opening into the receiving bore and is brought into contact with the free end of the chisel shank.
Then the handle can be pivoted until it rests against a support section. It is then possible to adjust the handle in the hinged connector with respect to the push-off section. The leverage thus created is introduced into the chisel via the push-off section so that the hold provided by the security element is released. Once the chisel is removed and the tool taken out, a fresh, unworn chisel can be placed against the receiving bore and driven in by a hammer. Changing a chisel by the known arrangement requires great force and, in case of tight space conditions, cannot be performed without danger.
Further removal arrangements are known from German Patent Reference DE 30 26 930 A1. These require a plunger, which is mounted in the area for the receiving bore of the chisel. The plunger can be linearly displaced against the shank end of the chisel, so that the chisel can be moved out of the receiving bore. Hydraulic systems or mechanical lever systems are employed for driving the plunger. These known tools require a lot of structural space, which cannot always be provided. Also, fine particles of the removed material enter the receiving bore designed as a blind bore during the operational use and cannot leave it again. They then impair the function of the removal arrangement and the free rotatability of the chisel in the insert.
Tools are known, which propose the insertion into or removal of a chisel from a chisel head. For example, German Patent Reference DE 43 23 669 C1, German Patent Reference DE 84 03 441 U1, U.S. Pat. No. 6,526,641 B1 and German Patent Reference DE 32 23 761 C2 show claw retractors that engage a circumferential groove in the chisel head with adjustable claws. For removal, the claws can then be adjusted in the longitudinal direction of the chisel. These known tools always require a shaped surface on the chisel head, behind which they can extend when pulling out the chisel. If this shaped surface is worn out because of heavy wear on the chisel, or if the chisel head is broken off, the tools are useless.